Question

Solve the system using substitution.
X + 5y = 0
3y + 2x = -21
([?], 1)

Answer 1

(-15, 3)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Equality Properties

Algebra I

• Solving systems of equations using substitution/elimination

Explanation:

Step 1: Define Systems

x + 5y = 0

3y + 2x = -21

Step 2: Rewrite Systems

x + 5y = 0

1. Subtract 5y on both sides: x = -5y

Step 3: Redefine Systems

x = -5y

3y + 2x = -21

Step 4: Solve for y

Substitution

1. Substitute in x: 3y + 2(-5y) = -21
2. Multiply: 3y - 10y = -21
3. Combine like terms: -7y = -21
4. Isolate y: y = 3

Step 5: Solve for x

1. Define equation: x + 5y = 0
2. Substitute in y: x + 5(3) = 0
3. Multiply: x + 15 = 0
4. Isolate x: x = -15